Dyed regenerated cellulose containing a polyamide



Patented Dec. 9, 1941 DYED REGENERATED CELLULO SE CONTAIN ING APOLYAMIDE William Way Watkins, Bnifalo, N. Y., assignor to E. I. du Pontde Nemours & Company, Wilmington, Del., a corporation of Delaware NoDrawing. Application March 9, 1939,

Serial No. 260,876

2 Claims.

This invention relates to the manufacture of artificial filaments,yarns, fibers, films, caps, bands, sponges, or similar structures havingan improved aflinity for dyestuffs. More particularly, the inventionrelates to the manufacture of such structures from cellulosic orsynthetic resinous compositions which have filmor filamentformingproperties.

Artificial filaments, fibers, films, and similar structures have beenproduced by spinning or casting operations. Thus, structures have beenproduced comprising or consisting of regenerated cellulose, as obtainedby the viscose or cuprammonium processes; cellulose derivativesincluding cellulose esters such as cellulose acetate, formate orpropionate and cellulose ethers such as methyl, ethyl or benzylcellulose, as well as mixed esters, mixed ethers, mixed ether-esters oreven mixtures of these; or synthetic resinous materials includingpolymeric vinyl compounds, such as polyvinyl chloride, polyvinylacetate, chlorinated polyvinyl chloride, interpolymers of polyvinylchloride and polyvinyl acetate as well as the polymers of acrylic ormethacrylic acid and their esters, such as methyl methaorylate and eveninterpolymers of methacrylate and vinyl chloride or the like.

Direct dyes possess the property of dyeing cotton, linen, andregenerated cellulose, as well as wool and silk, and form a veryimportant class of coloring materials. Direct dyes, in general, aredischargeable which is an important characteristic and is necessary forthe manufacture of an important class of textile fabrics known as printgoods. Acid dyes are used almost exclusively for dyeing wool, silk, andother animal fibers and are also extremely valuable.

Regenerated cellulose structures are readily dyed with direct colors.Regenerated cellulose, however, has practically no affinity for aciddyestuffs and when regenerated cellulose fibers are mixed with wool toproduce composite threads or yarns or when regenerated cellulose yarnsare fabricated with woolen yarns to produce mixed fabrics, the productcannot be dyed to a uniform color with acid dyestuffs. Although themixed fabric might be fairly uniformly dyed with a direct dye, it is attimes desirable and preferable to use acid dyestuffs because ofdifferences in lightfastness, laundry-fastness, etc., between directdye..- and acid dyestuffs.

Cellulose derivative structures and especially the cellulose esters suchas cellulose acetate can only be dyed with expensive special dyestuffsand by means of special, expensive and diflicult'procedures. For themost part, none of the cellulose acetate dyes are satisfactorilydischargeable and, consequently, cellulose acetate fabrics cannot besubjected to discharge printing as are fabrics of wool, cotton,regenerated cellulose rayon or the like. Furthermore, cellulose acetatehas no aflinity for either the acid or the direct dyes. It is because ofthis that cellulose acetate has been used to a considerable extent wherecrossdyeing effects are desired, but on the other hand when celluloseacetate is mixed with regenerated cellulose, cotton, wool or naturalsilk and a uniform solid color is desired, it has been necessary tosubject the same to several dyeing operations in separate dye baths orto go through a long expensive procedure attended by undesirable changesin the yarn or fabric properties. In the same way, structures preparedfrom synthetic resinous materials having filmor filamentformingproperties have been found to be highly resistant to the action ofcertain well known dyes. These resinous materials have little or noafiinity for either direct or acid dyes and. consequently, it has beenimpossible to secure suitable dyeing of film, filaments, yarns and thelike prepared therefrom.

In some cases the elevated temperatures necessary for dyeing with suchdyes as have been found useful, cause the materials to shrink ordeteriorate so that use of such dyes is impractical.

It is, therefore, an object of this invention to' improve the affinityof artificial films, filaments, and the like for dyestufis.

It is another object of this invention to improve the affinity of theseartificial structures for direct or acid dyestuffs.

It is another object of this invention to improve the afiinity ofregenerated cellulose structures for acid dyestuffs.

It is still another object of this invention to improve the aflinity ofcellulose derivative structures, such as cellulose acetate, for director acid dyestuffs.

It is still another object of this invention to improve the affinity ofsynthetic resinousfllmor filament-forming materials for either direct oracid dyestuifs.

Other objects will be apparent from the accompanying description andexamples.

Generally speaking, the objects of this invention can be accomplished byadding to the structure-forming composition as the case may be, discreteparticles of non-cellulosic, non-proteinous, linear polymeric compoundscontaining In the polyamides the amide groups form an integral part oi!the main chain of atoms in the polymer. These synthetic linearpolyamides may be prepared, for example, by a process of condensationpolymerization such as is described in Carothers U. S. Patents Nos.2,130,948, 2,130,523 and 2,071,253.

It has been found that a large variety of synthetic polyamides can beused to accomplish the objects of this invention depending on the typeof filmor filament-forming compositions from which the desiredstructures are to be produced. Generally speaking, a synthetic polyamidewill be chosen which will be insoluble or substantially so in the liquidvehicle used to make up the filrnor filament-forming composition. Iihus, for example, in the case of a regenerated cellulose structureobtained by the viscose process, the synthetic polyamide chosen will beone which is insoluble in water as well as in the caustic solutions usedto make up the viscose, and; the acid baths or the like subsequentlyused in the regeneration process. In the case of a cellulose acetatestructure, however, which is to be prepared by dry spinning or drycasting from a volatile solvent vehicle, the synthetic polyamide chosenmay be one which is water-soluble so long as it is insoluble in thesolvent or solvent mixture which is chosen as the vehicle for the filmorfilament-forming composition. Similarly, in the case of a syntheticresinous structure, such as a filament of an interpolymer of polyvinylchloride and polyvinyl acetate which can be spun by a dry spinningprocess, the synthetic polyamide will be chosen as one insoluble in thesolvent used to make up the spinning solution.

The following examples illustrate certain typical synthetic linearpolyamides which can be used in the practice of this invention. Theseexamples are, of course, to be considered as illustrative and notlimitative.

Example I Example II Three mols oi hexamethylene diamine and two mols ofadipic acid were dissolved in cresol usin a weight of cresol equal tothe weight of the reactant material. The mixture was heated in anitrogen atmosphere for 6 hours at 200 C.

after which the mixture was poured quickly into a relatively largevolume of ethyl acetate. A

flocculent, colorless, solid separated from the mixture which wasfiltered oil and washed with more ethyl acetate. The synthetic linearpolyamide so obtained exhibited and intrinsic viscosity of 0.15. It wassoluble in phenol and in formic or acetic acid, although it wassubstantially insoluble in the usual organic solvents.

Instead of the simple polymeric type illustrated by the above examples,numerous other synthetic polyamides can be used for the practice of thisinvention. Interpolymers can be used, as, for example, the interpolymerobtained by the co-polymerization of hexamethylene diammonium adipateand decamethylene diammonium sebacate or an esteramide interpolymer: e.g., one derived from a diamine, a glycol, and a dibasic acid. Likewise,polyamides obtainable from the reaction of adipic acid with diethylenetriamine or from the reaction of diglycolic acid with diethylenetriamine or from the reaction of tartaric acid. with hexamethylenediamine or from the reaction of maleic acid with hexamethylene diaminemay be used successfully.

Particularly desirableresults are obtainable by the use of linearpolyamides having a sumciently low molecular weight to have an intrinsicviscosity not in excess of 0.6. It has also been found that verydesirable results are obtainable by the use of that class of linearpolyamides which have a low molecular weight and are non-fiber formmg.

The molecular weight of synthetic linear polyamides may be controlled ina number of ways. If a diamine and a dibasic acid are allowed to reactin equivalent amounts, the molecular weight of the resulting polymer maybe controlled by adjusting the time of reaction, the temperature ofreaction, or, more conveniently, by adjusting the amount of water whichis present in the reactionvessel. It has been found that the presence ofa small amount of excess water' in the reaction vessel, along with thediamine and dicarboxylic acid, represses the polymerization sufiicientlyto give a polymer of the desired mechanical properties. The polymerprepared in this way may be readily ground to suitable particle size,and the incorporation of such polymer in films and filaments will permitthe dyeing of the latter with any number of the common silk and wooldyes.

Another and very convenient method of controlling the molecular weightis by the use of an excess of diamine or dicarboxylic acid, or othermonofunctional or difunctional acid or introgenous base. Thus, thereaction of 3 mols of diamine and 2 mols of dicarboxylic acid gives apolymer in the desired molecular weight range. The nature of the polymerproduced by this method may be quite different from that produced by theuse of equimolecular proportions of reactants; they are, however, verysuitable for use in accordance with the present invention. Not onlyissuch a polymer satisfactory in its solubility and grindingcharacteristics, but the acid dyestuffs are especially substantivethereto. Likewise, basic dyes are very substantive to a polymer preparedusing excess dibasic acid. N0 solvent is necessary irr conducting thepolymerization but, if desired, the phenols or cresols mayadvantageously be used; when the reaction is completed, the product maybe precipitated by the addition of a non-solvent, such as ethyl e ateand further ground up if n y- While it is preferred that the syntheticpolyamide employed shall be insoluble in the liquid vehicle used todisperse or dissolve the filmor filament-forming material, it ispossible to-use polyamides which show appreciable solubility. This isparticularly true in those cases where a dry spinning or dry castingprocess is to be employed because here, regardless of the solubility,when the liquid vehicle is removed by the evaporation step in theprocess, the synthetic polyamide will be left associated-with the filmorfilament-forming material. In the case where it is desired to modify aregeneratedcellulose Example III Thirty-six grams of thepolyhexamethylene adipamide described in Carothers U. S. Patent No.2,130,948, together with 60 cc. of water and grams of Monopole Oil wereplaced in a onequart ball mill and ground for 6 hours. The contents werethen washed out of the ball'mill with 257 cc. of water giving a slurrycontaining about 10% of the synthetic linear polyamide with an averageparticle size of some 3, to 5 microns.

One hundred seventeen grams of this slurry were then stirred into 1500grams of viscose using a high speed mixer. The viscosewas then deaeratedwhereupon it was spun in the usual manner using a conventional acidcoagulating bath. The resulting regenerated cellulose yarn was processedin the usual' way including desulfuring, bleaching, and washingoperations and then dried.

The finished yarn was dyed by immersing it in a bath maintained at 45 C.and containing 1% of Du Pont Anthraquinone Blue SKY (Color Index 1088),10% Glaubers salt and 4% acetic acid, the proportions of the ingredientsof the dye bath being calculated on the dry weightof the yarn. Thetemperature of the bath was slowly raised to about 85 C. and held atthat temperature for 45 minutes, the yarn beingturned frequentlyduring'the dyeing operation. The yarn was found to" dye quite deeply anduniformly with this acid dye for which unmodified regenerated cellulosehas little or no afiinity whatsoever.

Example IV A slurry of the synthetic polyamide described in Example IIwas prepared and added to viscose in the same way as described inExample III. The modified viscose was spun in the customary way into asaturated ammonium sulfate bath from which bath the coagulated butunregenerated yarn was conducted to a hot glycerin bath (temperature 125C.) wherein regeneration was efiected. The resulting regeneratedcellulose yam was washed, processed, and dried in the usual fashion andwhen subsequently dyed with an acid dye in the manner described inExample 111, the yarn was found to dye to highly satisfactory depth anduniformity.

. Example V H To a solution consistingof 0.25 gram eta-vinylchloride-methyl methacrylate interpolymer, 10

cc. of chloroform and 2 cc. of methanol, were.

added 0.05 gram of the interpolymer obtained by era-polymerization ofequal parts of hexamethyl -ene diammonium adipate and decamethylenediammonium sebacate. The mixture was poured onto the surface of aheated. glass slide and baked for 10 minutes in an oven 130 C. The thinfilm of modified synthetic resinous material was stripped from the palteeasily.

A dye bath consisting of 2 cc. of, 20% aqueous sodium chloride, cc. of0.2% aqueous dye solution, and 50 cc. of-distilled water was heated toC. and the resinous film material lmmersed therein for several minutes.After dyeing, the film material was washed with hot and cold distilledwater and dried. The film material modified with the synthetic polyamideexhibited marked dye receptivity whereas a similar film, unmodified,gave no indications of dye receptivity. Acid dyes such as Pontacyl FastBlue 5R Conc. (Color Index 289) and PontacyP' Fast Red A. S. (ColorIndex 176), while direct dyes such as Pontamine Blue RW (Color Index512) and the red dye obtained by Example I of U. S. Patent. No.1,940,683 were used, the dyeing time being 5 minutes for acid dye! and 7minutes for direct dyes.

Example VF procedure set forth in Example III, using Pentamine Fast Red8 BL (Color Index 278). The

yarn was found to be quite receptive to this dye for which normalcellulose acetate yarn had no aflinity whatsoever.

In order to efiectively improve the dye afllnity of thestructure-forming material, the synthetic polyamide may be added to thespinning or cast:

ing composition in concentrations as high as 30% or even more, based onthe weight of the structure-forming material present. In general,

however, it has been found that concentrations ranging from 5% to about20% depending, of course, on the effectiveness of the specific materialschosen, are suiiicient for most purposes. While it is possible toincrease the depth of dyeing by the addition of still larger quantitiesof the synthetic polyamide, increased depth of dyeing is frequentlyoffset by weakening of the structure so that from the practicalstandpoint, it is advisable to use no more of the synthetic polyamidethan is necessary to obtain the depth of color desired.

Film or filament structures of the type described which have beenprepared in accordance with the present invention have been found tohave particularly improved afiinity for so-called direct dyes, aciddyes, developed color dyes,- chrome dyes and vat dyes. The aflinity ofstructures for other dyes will also be im-' proved.

As illustrative examples of the above-mentioned classes of dyes forwhich the structures of the present invention have a satisfactoryaffinity may be mentioned:

Direct dyes Name Color index Pontamlne" Blue RW. 512 Pontainine" Sk Blue(iBX 518 "Pontamine Ye low CH. 365 "Pontamine" Green BX 593 Pontamine"Orange R 415 The red dye obtained by Example I of U. 8. Patent Acid dyesName Color index "PontacyP Wool Blue BL 833 PontacyY' Fast Red AS 1 76Pontacyl" Violet 04B 98 PontacyP' Fast Blue 5R Conc 289 Pontacyl" GreenNV Conc 735 Du Pout Anthraquinone Blue SKY 1088 Du Pont AnthraquinoneBlue B 1054 Du Pout Anthraquiuone Rubine R Conc 1091 Developed colordyes (diazo dyes) Pontamine Diazo Black BHSW Conc. (Color 7 Index 401).

The blue trisazo dye disclosed in U. S. Patent Also Developed" dyeshaving Color Index Nos.

317, 654, and 552.

" Chrome dyes "Pontachrome Blue R (Color Index 179). Du Pont ChromateBrown EB (Color Index Pr 12) Also chrome dyes having Color Index Nos.216,

40, 299, and 302.

Vat dyes Other dyes Basic dyes such as Methylene Blue (Color Index 922)and Rhodamine B (Color Index 749) may be used. 1

Basic substituted anthraquinone dyestuff commonly used to dye unmodifiedcellulose acetate rayon, such as the red dye l-methylaminoanthraquinone,the yellow dye l-nitro acridone, the blue dye1.4.5.B-tetra-amino-anthraquinone, the red-violet dyeIA-diamino-anthraquinohe, as well as such dyes as the orange dye4-nitro- .4'-amino-azobenzene may be used. Likewise,

dyesof the type of l-amino--arylamino anthraquinone-2-sulphonic acid maybe useful.

The color index numbers cited in the present specification are all takenfrom Rowes Colour Index," Society of Dyers and Colorists, first edition,1924.

It is understood, of course, that the structures provided by thisinvention may be dyed in accordance with any of the customary proceduresaccuse employed in the dyeing art for the particular type of dye chosen.4

In those cases where the film or filament structure comprises asubstantially water-insensitive material such as cellulose acetate or aconjoint polymer of vinyl chloride and vinyl acetate or an interpolymerof vinyl chloride and methyl methacrylate, the dyeing process can beexpedited by including in the dye bath a small amount of a solvent orswelling agent for the structureforming material. Thus, for example,.asmall amount of methyl Cellosolve or acetone added to the aqueous dyebath will facilitate the dyeing of a cellulose acetate structuremodified in accordance with the present invention. It is readilyunderstood, of course, that this is not a question of the effectivenessof the dye modifying ingredient, but obviously sincethe celluloseacetate, for example, is water-insensitive and since the dye bath is anaqueous medium, the ability of the dye to enter the film or filamentstructure is probably of a low degree. The addition of the solvent orswelling agent serves to facilitate the entry of the dye into thestructure so that the color can be retained by the dye modifying agentlight, washing and other factors tending to affect the color. Thematerials are definitely non-volatile and, therefore, resist removal byheat as in ironing operations. The synthetic linear polyamides are ofrelatively high molecular weight so that they are slow to diffuse fromthe fiber thus offering stability and fastness. I

By means of this invention synthetic filaments and yarns may be madeinto threads which can be mixed with wool, cotton, regenerated celluloseand the like and satisfactory dye results secured with any desired'classof dye. Fabrics made from cellulose derivative yarns or syntheticresinous yarns may be simply and inexpensively dyed with the desireddyestuif. In artificial structures such assponges, for example, thosemade from viscose, the invention finds particular application. In suchstructures, properties of luster. transparency,'etc., are very muchsubordinate to dye receptivity and this invention offers opportunity foruse of a large variety of dyes.

Since it is obvious that many changes and modiflcations can be made inthe above-described procedures and products without departing from thenature and spirit of the invention, it is to be understood that theinvention is not to be limited except as set forth in the appendedclaims.

I claim:

1. Regenerated cellulose films and filaments dyed with an acid dyestufiand containing, as an agent for promoting the afiinity of said films andfilaments for said acid dyestuff, 5% to 20% of finely divided discreteparticles of a synthetic linear polyamide, taken from the classconsisting of amino acid polyamides which, upon prolonged heating with adilute mineral acid, are hydrolyzed yielding the monomeric amino-acidfrom which they were derived, and diamine-dibasic acid polyamides which,upon heating with a strong mineral acid, are hydrolyzed to the dibasicacids and diamines from which they were derived, said polyamide havingrecurring structural units containing amide groups, the structural unitshaving a unit length of at least 7, said films and filaments exhibitinga uniform coloration throughout the body thereof.

2. Regenerated cellulose films and filaments 1U dyed with an aciddyestufi and containing, as an agent for promoting the aifinity of saidfilms and filaments for said dyestufi, 5% to 20% of finely divideddiscrete particles of a synthetic linear polyamide having an intrinsicviscosity not to ex- 15 tural units having a unit length of at least 7,said films and filaments exhibiting auniform coloration throughout thebody thereof.

WILLIAM WAY WATKINS.

